Water-soluble etherified starches

ABSTRACT

Aminated cellulose fiber obtained by adding one or more starches etherified with C 2  -C 5  -alkylamines which may additionally be substituted in the alkyl moiety by 1 to 2 further hydroxyl and methoxy groups and whose amino group is a primary or C 1  -C 4  -alkyl-substituted secondary, tertiary or quaternary amino or ammonium group and having a degree of substitution between 0.1 and 3 to a viscose dope, an alkali cellulose or a cellulose solution and spinning fiber therefrom.

Viscose fiber has essentially the same dyeing characteristics as cottonfiber. At present, the dyeing of natural or regenerated cellulosic fiberrequires the presence of alkali-donating agents and also electrolytes inorder that satisfactory fixation results may be obtained with reactivedyes. However, it is precisely these necessary additions which areecologically unacceptable. The future will therefore increasingly belongto regenerated cellulose fiber which is first, without additionalprocess steps, converted into modifications having a high dye affinity,i.e. modifications which are dyeable without salt and alkali. Fibermodified in this way resembles animal fiber, such as wool or silk, inits chemical behavior and it can be dyed under neutral conditions withanionic dyes without further salt or alkali additions.

A special field of application in this connection are blend fabrics, forexample fabrics composed of blends between polyester and modifiedviscose, which can then be dyed in a single bath.

Modifications of viscose have already been described in the literature.DE-A-1 948 487 describes a process for producing viscose fiber havingnovel dyeing properties. The fiber is produced using polyamineamides,which not only severely alter the native character of the fiber but arealso responsible for the unsatisfactory fastness level of the subsequentdyeing.

Similarly, DE-A-1 469 062 concerns "aminalized fiber". The additions areaminoethyl- and diethylaminoethyl-celluloses in high concentration, andthe dyeing is done exclusively with acid dyes. The disadvantage of thisprocess is that the additions first have to be complicatedly synthesizedand isolated and, what is more, are costly.

It is an object of the present invention to produce a viscose fiberhaving significantly more affinity for both reactive and direct dyes anddiffering positively from standard fiber in desired performancecharacteristics too.

This object is surprisingly achieved by admixture to a viscose dope,cellulose solution or alkali cellulose of starch derivatives highlysubstituted with amino-containing compounds and subsequent spinning.

The present invention accordingly provides aminated regeneratedcellulose fiber obtained by adding one or more starches etherified withC₂ -C₅ -alkylolamines which may additionally be substituted in the alkylmoiety by 1 to 2 further hydroxyl and methoxy groups and whose aminogroup is a primary or C₁ -C₄ -alkyl-substituted secondary, tertiary orquaternary amino or ammonium group and having a degree of substitutionbetween 0.1 and 3, preferably 0.11 to 2, in particular 0.2 to 1, to aviscose dope, an alkali cellulose or a cellulose solution and spinningfiber therefrom.

The etherified starch derivatives have a degree of substitution between0.1 and 3. A degree of substitution of 3 means that every one of thethree free OH groups in every glucose unit is etherified. A degree ofsubstitution of 0.1 means that, on average, every tenth glucose unit hasone etherified OH group.

Starches having a degree of substitution of about 0.05 are known per se(Houben-Weyl, 1987, Vol. E 20, part 3, pages 2135-2151), but starcheshaving a degree of substitution of 0.1 or higher have not been describedbefore.

The present invention therefore also provides above-describedalkylamino-etherified starch derivatives having a degree of substitutionbetween 0.1 and 3, preferably 0.11 to 2.

Preference for the purpose of the present invention is given to thosestarch ethers whose ether group has the formula --O--(CH₂)_(x) --NR₂,--O--CH₂ --CHOH--CH₂ --NR₂, --O--(CH₂)_(x) --SO₂ --(CH₂)_(y) --NR₂,--O--(CH₂)_(x) --SO₂ --(CH₂)_(y) --NR.sup.⊕₃ A.sup.⊖, --O--(CH₂)_(x)--.sup.⊕ NR₃ A.sup.⊖ or --O--CH₂ --CHOH--CH₂ --NR.sup.⊕₃ A.sup.⊖, wherex and y are each 2 or 3, the R radicals are identical or different andeach denote hydrogen, methyl or ethyl, and A is an anion, preferablychloride or sulfate. Particular preference is given to those starchethers whose ether group has the formula --O--CH₂ CH₂ --NH₂, --O--CH₂--CHOH--CH₂ --N⁶¹ (CH₃)₃ or --O--CH₂ CH₂ --N.sup.⊕ (CH₃)₃.

The novel starch ethers having said high degree of substitution formfluent to highly viscous materials in water ranging in viscosity from 1to 30 Pas (about 20% strength by weight aqueous solution), which, in theproduction of the regenerated cellulose fiber, can be added to thespinning dope, cellulose solution or alkali cellulose without furtherworkup.

The degree of polymerization of the starch ethers of this invention isadvantageously between 100 and 1000, preferably ably 100 and 400,anhydroglucose units. If the degree of polymerization were smaller than100, the starch ether could be washed out of the fiber after spinning.

The starch ethers of this invention are prepared by reacting any desiredstarch, for example potato starch, maize starch or wheat starch, with aC₂ -C₅ -alkylamine having a substituent reactive toward OH groups, forexample α-chloro-β-hydroxyl, 1, 2-epoxy, 1-(sulfatoethyl sulfone.) orsulfatoethyl substitution, at a pH of 9 to 14, preferably 9.5 to 13. Thereaction temperature is advantageously 40 to 100° C. The C₂ -C₅alkylamine is reacted in a molar ratio of alkylamine:anhydroglucose unitof 0.1:1 to advantageously 4:1, depending on the degree of substitutiondesired for the starch.

Examples of the aforementioned alkylamines which are used for modifyingthe starch are glycidyl trimethylammonium sulfate or chloride,sulfatoethyltrimethylammonium sulfate or chloride, aminoethyl sulfate,3-chloro-2-hydroxypropyltrimethylammonium sulfate or chloride andaminopropyl sulfatoethyl sulfone.

The starch ethers used for producing the aminated regenerated cellulosefiber, being soluble in water, are readily dispersible directly in thespinning dope, preferably in an aqueous medium optionally with the aidof emulsifiers, and exhibit good compatibility with the viscose. Thefluent starch ether is added in an amount of 1 to 20%, preferably 1 to12% by weight, calculated as dry substance, based on the cellulosecontent of the spinning dope, prior to coagulation and shaping. Thefilterability of the viscose shows no deterioration compared withaddition-free samples, so that no plugging of the spinneret is to beobserved in the course of the spinning process. The shaping of theviscose is carried out by customary and known methods, for example bymeans of spinnerets, a subsequent coagulation bath and optionallyfurther aftertreatment baths.

Another way of producing the aminated regenerated cellulose fiber is tostir the starch derivatives mentioned into the alkali cellulose, aprecursor of the viscose. Again, following xanthation and extrusion intoan acidic coagulation bath, an aminated viscose fiber is obtained.

The fiber obtained by the methods described can, after processing intowovens and knits, be dyed by various processes, such as exhaust, paddingand modern printing processes, such as inkjet processes, without use ofsalt or alkali.

The present invention also provides a process for producing a dyed orprinted textile material composed of regenerated cellulose fiber, whichcomprises adding said starch ethers to a viscose dope, cellulosesolution or alkali cellulose and spinning fiber, for example by theviscose spinning process or from the cellulose solution, processing thefiber into a woven or knitted fabric and dyeing or printing said fabricwith one or more reactive dyes in the absence of additional electrolytesalt or alkali.

The textile modified fiber material which is used in the dyeing processof the invention can be present in all processing states, for instanceas yarn, staple, slubbing and piece goods (fabrics).

The modified textile materials are dyed according to the presentinvention analogously to known processes for dyeing and printing fibermaterials with water-soluble textile dyes and through the use of theknown temperature ranges and customary dye quantities, except that thedyebaths, padding processes, print pastes and inkjet formulationsrequire no addition of alkaline compounds, as customary for fixingfiber-reactive dyes, nor customary additions of electrolyte salts.Dyeing or printing therefore takes place at a pH between 4.5 and 8.5and, if commercially available reactive or direct dyes are used, in thepresence of an electrolyte salt content of 0.01 to 0.5% by weight, basedon the dyeing solution. Without the novel amination of the cellulosefiber, this electrolyte content would be too low for successful dyeingby a factor of 20 to 1000.

Suitable dyeing processes for the purposes of this invention include forexample the various exhaust processes, such as dyeing on the jigger oron the reel beck or dyeing from long or short liquor, dyeing in jetdyeing machines, dyeing by short-time pad-batch processes or by apad-superheated steam fixation process. Suitable dyeing processes forthe purposes of this invention also include printing techniques, forexample inkjet printing and transfer printing.

The dyes which are used for dyeing the modified cellulose are generallyanionic in nature. Of particular suitability are the fiber-reactivetextile dyes which are capable of reacting with hydroxyl groups, forexample of cellulose, or amino and thiol groups, for example of wool andsilk, of synthetic polymers, such as polyamides, or else modifiedpolymers, specifically the aminated celluloses, to form a covalent bond.Suitable fiber-reactive components on the textile dyes include inparticular sulfatoethylsulfonyl, vinylsulfonyl, chlorotriazinyl,fluorotriazinyl, and also combinations thereof.

Suitable acid or direct dyes for dyeing or printing cellulose fibermodified according to this invention include for example the diaminedyes, ®Sirius Light Fast dyes, ®Alphanol dyes, ®Cotonerol dyes and®Duasyn dyes, such as, for example, C.I. Acid Black 27 (C.I. No. 26310), C.I. Acid Black 35 (C.I. No. 26 320), C.I. Acid Blue 113 (C.I. No.26 360), C.I. Direct Orange 49 (C.I. No. 29 050), C.I. Direct Orange 69(C.I. No. 29 055), C.I. Direct Yellow 34 (C.I. No. 29 060), C.I. DirectRed 79 (C.I. No. 29 065), C.I. Direct Yellow 67 (C.I. No. 29 080), C.I.Direct Brown 126 (C.I. No. 29 085), C.I. Direct Red 84 (C.I. No. 35760), C.I. Direct Red 80 (C.I. No. 35 780), C.I. Direct Red 194 (C.I.No. 35 785), C.I. Direct Red 81 (C.I. No. 28 160), C.I. Direct Red 32(C.I. No. 35 790), C.I. Direct Blue 162 (C.I. No. 35 770), C.I. DirectBlue 159 (C.I. No. 35 775), C.I. Direct Black 162:1 and C.I. DirectViolet 9 (C.I. No. 27 885).

Unless otherwise stated, parts and percentages in the examples whichfollow are by weight.

The molar masses of the starches used are customarily based on oneanhydroglucose unit.

EXAMPLE 1

a) Preparation of the starch ether:

162 g (1 mol) of potato starch, technically dry, are added in a kneaderto 500 ml of water in which 26.4 g (0.66 mol) of sodium hydroxide havebeen dissolved beforehand. Then 130 g (0.6 mol) of2,3-epoxypropyltrimethylammonium chloride are added as 70% strengthsolution in water. The mixture is kneaded at 60° C. for 4 hours, cooleddown to room temperature and adjusted with sulfuric acid to pH 6. Theviscosity is 5.6 Pas at 50° C. and 19.6 Pas at 20° C.

To further characterize the starch derivative, 5 parts of the viscousmass are dissolved in 100 parts of water and freed of unconvertedepoxide and neutralization salts by means of a membrane desaltingtechnique. The purified starch derivative is evaporated to dryness underreduced pressure. The degree of substitution is determined via anitrogen assay of the modified starch. The nitrogen content was 3.5% inthe present case. The degree of substitution is calculated according tothe following formulae:

    162+151/14×[%N]=MW

    [%N]/14×MW: 100=[degree of substitution]

The modified starch accordingly has a degree of substitution of 0.67.

b) The starch derivative thus obtained is incorporated into aplant-customary fiber-grade viscose having a cellulose content of 8.9%,an alkali content of 5% and a viscosity at 30° C. of 38 falling-ballseconds as follows: 50 parts of the modified starch are mixed with 436parts of fiber-grade viscose. This premix is stirred into 2522 parts offiber-grade viscose.

After devolatilization the spinning dope is spun by plant-customaryviscose spinning processes into a bath comprising sulfuric acid, sodiumsulfate and zinc sulfate to form fiber, which is stretched in acidicbaths, cut, washed, spin finished and dried.

c) 10 parts of this dry viscose fiber is then admixed in a dyeingapparatus with 100 parts of water. The temperature is raised to 60° C.and a total of 0.1 part of a 50% strength electrolyte(predominantlysodium chloride)--containing dye powder of formula, known from DE-A-1943 904 ##STR1## is metered in over a period of 30 minutes. Following afurther liquor circulation period of 5 min the remaining, almostcolorless liquor is dropped and the material is conventionally washedout and dried. The result obtained is a strong,deep red dyeing havingvery good use fastness properties.

EXAMPLE 2

10 parts of the viscose fiber modified as described in Example 1 aretransferred into a dyeing apparatus and treated in a liquor ratio of10:1 with an aqueous liquor which, based on the weight of dry fiber,includes 0.1 part of a reactive dye of the formula, known from Example106 of EP-A-0 457 715 ##STR2## in solution. The fiber is dyed at 60° C.for 30 minutes. The dyeing thus produced is further treated by rinsingand soaping in a conventional manner. The result obtained is a deep reddyeing having very good use fastness properties.

EXAMPLE 3

A fiber-grade viscose as described in Example 1 is admixed with a starchsynthesized according to the following description:

200 g (1.2 mol) of maize starch are added in a 2 l flask fitted with adownward-moving stirrer to 500 ml of water and 24 g (0.6 mol) of sodiumhydroxide. 113 g (0.4 mol) of sulfatoethyltrimethylammonium sulfate,dissolved in 300 ml of water, are then added to the mixture. Theresulting mixture is stirred at 85° C. for 6 hours, if necessary keptstirrable by further addition of water, cooled down to room temperatureand adjusted with sulfuric acid to pH 6. The starch ether has a degreeof substitution of 0.3.

The product is stirred into the viscose as described under Example 1.Following devolatilization the spinning dope is spun by plant-customaryviscose spinning processes into a bath comprising sulfuric acid, sodiumsulfate and zinc sulfate to form fiber, which is stretched in acidicbaths, cut, washed, spin finished and dried.

Weaving thus gives a textile viscose fabric which can be furtherprocessed directly in a pad-dyeing process. For this the fabric hasapplied to it at 25° C., by means of a pad-mangle, an aqueous dyesolution which, per 1000 parts by volume, includes in solution 20 partsof the dye of the formula ##STR3## known from Example 1 of EP-A-0 158233, and 3 parts of a commercial nonionic wetting agent, to a liquorpickup of 80%, based on weight of fiber. The fabric padded with the dyesolution was wound onto a batching roller, wrapped in plastic film, leftfor 4 hours at from 40 to 50° C. and then rinsed with cold and hotwater, which may contain a commercial surfactant, and if necessarysubsequently rinsed once more with cold water and dried. The resultobtained is a strong level yellow dyeing which has good allroundfastness properties, especially good rub and light fastness properties.

EXAMPLE 4

A modified fiber-grade viscose described as under Example 1 is spun bythe process steps customary for fiber-grade viscoses to form a fiber,which is reactive-dyed in an exhaust process without added salt oralkali. To this end, 30 parts of the viscose fiber are wound on apackage and the yarn is treated in a yarn dyeing apparatus whichcontains 450 parts, based on weight of fiber, of a liquor which contains0.6 part, based on the initial weight of the goods, of an electrolyte(predominantly sodium chloride)--containing dye of the formula knownfrom Example 1 of DE-A-2 840 380 ##STR4## and heated to 60° C., theliquor being pumped alternately in to out and out to in. After 60 min atthis temperature the liquor is dropped, and the dyeing obtained isrinsed and washed under the customary conditions. The result obtained isa level yellow fiber having the generally good fastness properties ofreactive dyes.

Further Preparation Examples 5-7 for modified starch ethers

In each case 162 g of potato starch are added to 500 ml of water and26.4 g of sodium hydroxide similarly to Example 1. This mixture is ineach case admixed with the following modifiers and further processed andassayed for their degree of substitution as in Example 1:

5) Aminopropyl Sulfatoethyl Sulfone of the Formula ##STR5##

Degree of substitution: 0.26.

6) 3-Chloro-2-hydroxypropyltrimethylammonium chloride Degree ofSubstitution: 0.35.

7) Aminoethylsulfuric acid Degree of Substitution: 0.31

Examples of Dyeings with Direct Dyes:

EXAMPLE 8

Example 1 is repeated to obtain, on weaving,a textile viscose fabricwhich can be further processed directly in a pad-dyeing process. Forthis, the fabric has applied to it at 25° C., by means of a pad-mangle,a dye solution which, per 1000 parts by volume, includes 20 parts of theacid dye of the formula ##STR6## (Pc--phthalocyanine)

(C.I. Direct Blue 199) and 3 parts of a commercial nonionic wettingagent, to a liquor pickup of 80%, based on weight of fiber. The dyesolution has beforehand been adjusted to pH 5 with acetic acid. Thefabric padded with the dye solution is then steamed for 2 minutes. Thedyeing thus produced is further treated by rinsing and soaping in aconventional manner. The result obtained is a strong turquoise dyeinghaving very good allround fastness properties.

EXAMPLE 9

A viscose modified as in Example 3 is passed by means of one or tworolls for guiding and tensioning the fabric underneath an inkjetprinting head and printed with aqueous solutions of direct dyes. Toobtain multicolored prints, a four-color print is carried out with theprimary colors of subtractive color mixing (yellow, cyan, magenta andblack). The cyan dye used was C.I. Blue 199, the yellow dye used wasC.I. Direct Yellow 34 (C.I. No. 29060), the magenta dye used was C.I.Direct Red 79 (C.I. No. 29065), and the black component used was C.I.Direct Black 162:1. The printer operates according to the drop on demandprocess and the ink droplet is created thermally (bubblejet process).The printed fabric is subsequently steamed for 2 minutes and thenconventionally rinsed and soaped. The resulting print has good allroundfastness properties.

EXAMPLE 10

Example 6 is repeated, the viscose worked up and the fiber woven up.

A viscose modified in this way is applied to a rotating roll. Acontinuous-flow printing head then issues a continuous stream ofdroplets of direct dye which, under computer control, reach the viscoseor are deflected. To obtain multicolor prints, a four-color print iscarried out with the primary colors of subtractive color mixing (yellow,cyan, magenta and black). The cyan dye used is C.I. Blue 199, the yellowdye used is C.I. Direct Yellow 34, the magenta dye used is C.I. DirectRed 81 and the black component used is C.I. Acid Black 35. The printedfabric is subsequently steamed for 2 minutes and then conventionallyrinsed and soaped. The resulting print has good allround fastnessproperties.

EXAMPLE 11

A viscose fiber produced according to Example 1 is converted into awoven fabric following further processing by the process steps customaryfor viscose fiber and dyed.

For this, the fabric is guided by means of two rolls for guiding andtensioning the fabric underneath an inkjet printing head and printedwith aqueous solutions of direct dyes. The printer operates according tothe drop on demand process and the ink droplet is generated by the piezoprinciple. To obtain multicolor prints, a four-color print is carriedout with the primary colors of subtractive color mixing (yellow, cyan,magenta and black). The cyan dye used is C.I. Blue 199, the yellow dyeused is C.I. Direct Yellow 67, the magenta dye used is C.I. Direct Red81 and the black component used is C.I. Acid Black 27. The printedfabric is subsequently steamed for 2 minutes and then conventionallyrinsed and soaped. The resulting print has good allround fastnessproperties.

FURTHER EXAMPLES

Example 1 is repeated with similar results using the below-listed dyes:

    ______________________________________                                        C.I. Direct Violet 9 C.I. No. 27885                                             C.I. Direct Brown 126 C.I. No. 29085                                          C.I. Direct Orange 69 C.I. No. 29055                                          C.I. Acid Blue 113 C.I. No. 26360                                             C.I. Acid Blue 40 C.I. No. 62125                                            ______________________________________                                    

What is claimed is:
 1. A water-soluble etherified starch, the ether substituents being groups of the formula --O--(CH₂)_(x) --SO₂ --(CH₂)_(y) --.sup.(+) NR₃ A.sup.(-) wherein x and y are each 2 or 3, and the R-radicals are identical to one another or different from one another and each denotes hydrogen, methyl or ethyl, and A⁻ is an anion.
 2. The water-soluble etherified starch according to claim 1, wherein said etherified starch has a degree of substitution between 0.11 and
 2. 3. The water-soluble etherified starch according to claim 1, where the degree of polymerization of the etherified starch is between 100 and 1000 anhydroglycose units.
 4. The water-soluble etherified starch according to claim 3, where the degree of polymerization is between 100 and 400 anhydroglucose units.
 5. The etherified starch of claim 1, wherein A.sup.⊖ is chloride or one equivalent of sulfate. 